Researchers analyzing hundreds of studies say vitamin D supplements won’t protect healthy, middle-aged adults from osteoporosis. And even worse, they say the supplements may increase the risk of death from other diseases.
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But make sure you aren’t deficient in vitamin D before you stop taking the supplement, say Cleveland Clinic bone health experts.
“The take-home message for patients with vitamin D deficiency should not be ‘you won’t benefit from vitamin D supplementation, vitamin D can have a positive impact,” says rheumatologist Chad Deal, MD.
Adds rheumatologist Johnny Su, MD, “If you are healthy and are not getting treatment for any medical problems, you don’t have to worry about starting supplements. But if you are now taking supplements, be sure to get your vitamin D levels checked before stopping.”
Who still needs their D
People in the following categories should keep taking vitamin D supplements, says Dr. Su:
- Postmenopausal women
- Men and women on long-term steroids
- Elderly people (homebound or in nursing homes/assisted living)
- Expectant and breastfeeding mothers
- People with chronic kidney disease
- People with parathyroid disease
If you aren’t sure if you’re at risk for vitamin D deficiency, Dr. Su recommends asking your healthcare provider to check your vitamin D level. He or she should work with you — and repeat the easy blood test — to make sure you’re taking the right amount of supplement.
Calcium and vitamin D: a partnership
Calcium and vitamin D work in tandem to strengthen and protect your bones. For years, experts have recommended that postmenopausal women take calcium and vitamin D supplements to prevent osteoporosis. The bone-thinning disease is a major cause of devastating fractures in old age.
But research linking calcium supplements to heart attack and stroke caused many to turn to vitamin D supplements for prevention. “Calcium supplements can increase calcification in the arteries and predispose people—especially women—to heart disease. That is why we always prefer dietary calcium,” explains Dr. Su. “However, some people may get adequate dietary calcium but may be low in vitamin D.”
Your skin must manufacture vitamin D from sunlight, but sun exposure should not be your main means of boosting vitamin D, he adds. It’s important to wear sunscreen to protect against skin cancer — but that negates the sun’s effects on vitamin D production.
Fracture protection: What the studies say
For older patients at risk of vitamin D deficiency, Dr. Deal notes that supplements can have a major impact. Severe vitamin D deficiency can result in osteomalacia, a softening of the bone that makes fractures more likely.
In January 2014, a University of Auckland meta-study made waves by showing that vitamin D supplements alone had little effect on bone density.
This was not surprising, says Dr. Deal. “We would not expect vitamin D supplements to have a large impact on bone density unless the deficiency was severe. Then their impact could be significant.”
Benefits for bones, muscles, thinking
Dr. Deal explains that improving bone density is not the only way to prevent fractures — especially in older patients. “Vitamin D can also have huge benefits for muscle function, cognition and falling,” he says.
In April 2014, two additional meta-studies on vitamin D appeared. A University of Edinburgh study found no evidence that vitamin D supplements reduced mortality, or prevented falls or fractures. A University of Cambridge study found no evidence that vitamin D supplements reduced overall mortality. (Drilling down into the type of supplement taken, however, vitamin D3 significantly reduced mortality while vitamin D2 slightly increased mortality.)
Experts on all sides agree on the need for more research on vitamin D.
What you can do now
“If you are concerned about vitamin D deficiency, ask your healthcare provider to check your vitamin D level,” says Dr. Su. “If the level is low and your provider starts you on supplements, you need repeat testing in eight to 12 weeks to make sure the level is not too high or too low.
“If testing shows your vitamin D level is normal, you need repeat testing every two to three years unless you have major changes in your overall health.”
If you have chronic kidney disease or parathyroid disease, ask your kidney specialist or endocrinologist about the type and dose of vitamin D you need, he says. And if you are pregnant or breastfeeding, keep taking vitamin D supplements as long as your obstetrician prescribes them.
Other good advice for bone health: stay active and remember a calcium-rich diet.